Mold growth is a common problem in Canadian households. Mold problems tend to be more prevalent in older homes and in homes in wetter, rainier parts of the country (such as the east/west coast). However, all homes are subject to mold growth at some level, regardless of age, size, location or other factors.
Not all molds are the same. Some varieties are beneficial, like the kind used to produce penicillin or flavor certain foods (like cheese). Others may not be particularly beneficial, but they aren't terribly harmful either.
Then there are those, such as Stachybotrys, which can wreak havoc with a person's respiratory system. This type is the one most commonly found growing in homes and other buildings. It is often referred to as 'black mold' because of its dark green/blackish color.
All types of mold thrive in moist environments. In addition to moisture, Stachybotrys prefers high-cellulose surfaces, like the kind on drywall, fiberboard and other materials commonly used in home construction.
High levels of Stachybotrys in a home can lead to poor respiratory health and breathing problems. It is particularly dangerous for people with pre-existing respiratory issues like asthma, leading to worsening symptoms and more frequent attacks. It can also cause a person to develop flu-like symptoms, such as dizziness, fatigue and headaches, which simply don't go away. The only way to treat the problem is to eliminate the mold.
Remediation and mold abatement, unfortunately, is expensive. It can cost anywhere from thousands to hundreds of thousands of dollars, depending on the extent of the problem.
Preventing mold is far less costly than eliminating a problem that has already taken root. In addition to other measures like vapor barriers in walls, proper insulation and sealed windows, the right HVAC system can help prevent mold growth.
Your HVAC system circulates the air in your home through a set of ducts. It pulls in air at one end, through the ducts and eventually to a filter or series of filters. The filter(s) traps contaminants like mold spores and keeps them from blowing back out into your house.
First, choose a system that is the right size for your home. This will help ensure that air is always circulating efficiently no matter what season it is.
Your HVAC system itself is designed to repel mold. Because your ducts are made of metal, mold cannot grow inside of them. Instead, it will be caught inside of the system's filter instead of circulating back into your home.
Next, set your humidity control for its optimal level. Generally speaking, your home humidity level should be under 60 percent in summer and between 25 and 40 percent in winter. You may need to adjust this recommendation if you live in a very wet or very dry region. (Ask your local refrigeration mechanic for advice.) Your home should be moist enough to be healthy and dry enough to discourage Stachybotrys from taking hold.
Your humidity control works by detecting how much moisture is in your home's air. If it exceeds the level you've set your control for it will cause your fan to turn on automatically to dry out the air. It will shut off automatically once the humidity level has dropped to your desired setting.
You may need to augment your system with a free-standing de-humidifier, especially if you have an older HVAC and/or a larger home. Place de-humidifiers in areas of your home that are prone to moisture, such as around bathrooms.
Finally, make sure that your entire system is properly installed and maintained. Always choose a professional, qualified HVAC technician for installations and repairs.
Always keep your system clean. A dirty HVAC system will naturally result in dirty indoor air. Have your system and your ductworks cleaned regularly (every 2-3 years).